1. Field of the Invention
The present invention relates to a multifocal lens array and to a three-dimensional stereoscopic image display apparatus that displays a three-dimensional stereoscopic image in three-dimensional space.
2. Description of the Related Art
It is anticipated that display of stereoscopic images will be widely used in fields such as the following so long as the display performance and cost are appropriate. In the medical field, by displaying stereoscopic data from a CT scan or the like in space, a diseased site can be identified before surgery, which is very useful. In construction, by viewing CAD data stereoscopically, spatial checking of areas can be carried out, which again is useful. In facility design, robot design and so on, the spatial arrangement of components can actually be seen, and hence design can be carried out with no waste. Moreover, in town planning and regional development, by carrying out studies using a three-dimensional stereoscopic image, more realistic studies can be carried out. In air traffic control, the positions and altitudes of airplanes can be checked instantly, and hence dangerous situations such as near misses can be reduced. In defense, three-dimensional terrain information and spatial information can be grasped instantly, and hence there would be many opportunities for use. In entertainment, i.e., in fields such as gaming in which enjoyment is had while manipulating images, one can anticipate novel types of entertainment in which a plurality of people simultaneously view or manipulate a stereoscopic image from a variety of angles.
For displaying a three-dimensional stereoscopic image in three-dimensional space, there exists a method in which the difference in viewing angle between the left and right eyes is used so as to enable a person to see stereoscopically, and a method in which display is actually carried out in three-dimensional space so as to enable viewing from all directions over 360°. As a method in which display is actually carried out in three-dimensional space, there is, for example, a method in which a stereoscopic image is actually displayed in space using lasers as in, for example, Japanese Patent Application Laid-open No. 2000-338900.
However, for methods in which the difference in viewing angle between the left and right eyes is used, as in, for example, Japanese Patent Application Laid-open No. 2000-115812, U.S. Pat. Nos. 6,525,699, 6,940,473, 6,950,078, and 7,002,532, there exists the problem that, while a stereoscopic image can be seen when viewed from a certain direction, when viewed from another place either viewing is not possible or a stereoscopic image cannot seen. Moreover, in the case of using lasers or the like, there is a problem that the apparatus is large and hence there are limitations on the installation site due to restrictions relating to size, weight and so on, and, moreover, the cost is high.